I did it for a practice go really, while i wait for some leather. I got a full set with the red and blue stripes on for twenty five quid. There are a lot better than the RT seats.
The best advice is take your time with the backs and it will fit eventually.
Ive got to say hat leather looks mint, i just have to be patient and wait for mine. Has anyone ever heard of fitting renault 21 leather ?? I know that you will need to change the frames but will the rear cussions be too big ??